1. Field of the Invention
The present invention relates generally to data entry keyboards, and more specifically to an adjustable keyboard with adjustable divided key fields synchronized by a synchronous gearing mechanism.
2. Art Background
Since the advent of the "standard keyboard" employed in ordinary typewriters, various modifications have been made to simplify the mechanics and improve the human factors of keyboard use. Such modifications have included altering either the arrangement of keys or changing the overall structural design, or both. For example, in German laid-open description No. 27 25 677 to Muther, entitled "Tastatur fuer Schreibmaschinen (Typewriter Keyboard)", an alternative arrangement of key order and placement is disclosed wherein improved typing speed can be achieved by placing the most frequently struck keys at the "home" position for the eight typing fingers. The keyboard of Muther is a unitary key field distributed in a fixed base, where the keys are arranged in wave-like rows.
In U.S. Pat. No. 4,597,681 to Hodges, entitled "Adjustable Keyboard", a keyboard arrangement is disclosed wherein two sets of keys can be pivoted and tilted, as well as having adjustable keycaps to achieve a comfortable typing position for a user. In Hodges, the sets of keys are contained within two hingeably attached baseplates positioned within an underlying support plate. However, the sets of keys in the Hodges keyboard must be separately adjusted in both the pivoting and tilting dimensions, and the complex construction of the adjustable keycaps can significantly increase the cost of manufacture of the keyboard.
In U.S. Pat. No. 5,067,834 to Szmanda et al., entitled "Input Keyboard Apparatus for Information Processing Device and Other Keyboard Devices", an adjustable keyboard is disclosed wherein two sets of keys can be pivoted and tilted to a comfortable position for the user. In Szmanda, a universal pivot point and a pair of telescoping members are used to articulate and support the keyboard arrangement in a desired position. As in the Hodges patent, the sets of keys in the Szmanda keyboard must be separately adjusted in both the pivoting and tilting dimensions.
Due to the nature of the articulating and adjusting hardware components used in recent "improved" keyboard designs, such keyboards may be less attractive to users from both cost and convenience considerations. Depending upon the working height of the keyboard, as the key fields of the articulating keyboards of Hodges and Szmanda become substantially elevated above the work surface, a user may experience discomfort if the palms and forearms of the user are not supported.
Moreover, existing adjustable keyboards comprising two key fields treat the space bar in one of two ways. First, the space bar may be "split" into two portions as taught by Hodges, with each key field containing one of the two space bar portions. Second, an elongated, full-sized space bar fixed relative to one of the key fields is used, and remains fixed relative to one of the key fields comprising the keyboard, generally the right key field, as the keyboard components are repositioned. The foregoing space bar arrangements can produce undesirable results. For example, an open space, or gap, will be created in the region between the separated key fields normally occupied by a "standard space bar when the articulating keyboard is adjusted outward, the gap occurring in the region where the space bar is most commonly struck by a user's thumb. Further, two separated key fields using the two-portion split space bar may also cause the user to become disoriented as to hand or key position. Alternatively, in arrangements using an elongated space bar fixed relative to one of the key fields, the space bar will create an awkward extension when the key fields are articulated outward during use.
As will be described in more detail in the following detailed description, the present invention facilitates a comfortable and easy to use integrated keyboard arrangement comprising a space bar which remains generally centrally disposed between two articulating key fields, which keyboard may be used with data entry or computing devices. Further, the present invention provides for synchronizing means including a synchronizing gear to permit synchronized or complimentary motion between the movable component parts, thereby permitting easy positioning of the separate key fields in an efficient manner relative to the stationary space bar. The synchronizing gear allows transmission of force in only one direction of gear rotation, enabling a gear tooth to be significantly thicker than a prior art gear tooth, and therefore stronger and more reliable.